"The NZXT HALE90 750W power supply got a little warm during testing thanks to a cooling fan that remained at or around 700 RPM at all times. I've come across this same behaviour very recently and on investigation the Sentey Golden Steel Power 850W and the NZXT HALE90 750W are based on the same Super Flower design. The introduction of a little warm air into the NZXT HALE90 750W power supply, like the Sentey, caused the cooling fan speed to ramp up to 1400 RPM."